The previous X games were good, but I find X$ has a better balance of interface improvements, training help files, etc...
I like that you have a fast travel mode.
The whole game seems better balanced for the more casual gamer (myself) and complex enough for those who like a more intense challenge.
A few ideas came to me that might be easy to implement and improve immersion and make the game even better.
Some areas could be more interesting if they contained mini games.
For example:
Hacking could be better accomplished with a mini game like the one used in Fallout 3. I believe it was a take on the codebreaking board game MasterMind. I found that most enjoyable.
Likewise satellite repair could be a minigame involving resistors and capacitors? Or some sort of slide 15 puzzle?
I only have 40 hours in the game, but I am sure I will encounter more places where mini games might spice up the game.
Same with decrypting signal leaks. Some sort of math puzzle, or maybe a game of 'Simon' (color sequence remembering)?
Maybe even scanning could be improved in this area.
The lock boxes already are their own coordination / timing mini game and I find that enjoyable.
Landing already is a mini game. It was nicely implemented.
If implemented, maybe they could be turned off in settings for those who don't want more fun in their games

Keep up the good work!